This invention relates to optical switches and particularly relates to optical switches employing reflectors which selectively reflect light into a fiber optic cable or light conductor by rotating between bistable positions. Typically, these reflective switches are used in conjunction with an optical signal transceiver which generates a light beam transmitted through the fiber optic cable and senses a return signal to determine whether or not a reflector at an opposite end of a cable is reflecting any substantial portion of the light.
Optical signals have a number of advantages over electrical signals in certain circumstances, particularly those involving potential hazards. There is no electric shock potential from an optical signal nor can an optical signal spark to ignite a flammable or explosive environment. As a result, optical signals are particularly useful in NEMA Classes 7 and 9 and NEC Classes 1 through 3 Division One and Division Two. Optical signals are also relatively immune to dampness and electromagnet interference. Examples of such transceivers and switches are shown by U.S. Pat. No. 4,878,729 and U.S. Pat. No. 4,903,337.
U.S. Pat. No. 4,878,729 issued to David G. Stewart on Nov. 7, 1989 describing an OPTICAL SWITCH and assigned to the assignee of the present invention.
U.S. Pat. No. 4,903,337 issued to Edwin R. Newell et al on Feb. 20, 1990 describing a FIBER OPTICAL TRANSCEIVER and is assigned to the assignee of the present invention.
Each of the foregoing patents and applications owned by Square D Company are incorporated herein by reference.